1. Field of the Invention
The present invention relates to electrophotographic copiers having a function for recording additional information such as dates and/or page numbers.
2. Description of the Prior Art
Electrophotographic copiers having a function for recording additional information are known in the art. Copiers of this type comprise a recording head for recording additional information on a photoreceptor, besides ordinary image-forming elements for projecting an image of an original onto the photoreceptor to form an electrostatic latent image of the original thereon.
U.S. Pat. No. 4,640,601 discloses an example of such electrophotographic copiers, which comprises, in addition to a lens array for projecting an image of an original onto a photoreceptor, an LED array for recording additional information on the photoreceptor, and a shield member driven to advance to a position between the original and the lens array for preventing the original image from being projected to a region of the photoreceptor on which the additional information is to be recorded. With the copier disclosed in this U.S. patent, when the original image is projected onto the charged photoreceptor, the shield member intercepts the light directed to a partial region of the photoreceptor to retain the charge in that region. Thereafter, the region is exposed to the LED array for writing the additional information thereon. The LED array is movable axially of the photoreceptor for allowing the additional information to be recorded on a selected position of the photoreceptor.
However, the copier disclosed in the above U.S. patent must provide a space for accommodating the movement of the shield member which is movable together with the LED array. This copier is therefore unsatisfactory from the point of view of compactness.